You can still use https:// for unauthenticated access to public repos.
Not a big deal but just something that to my knowledge you won't be able to do going forward.
What I'm talking about is this: with a git:// URL, if you plug it into Git and that repo is private, you just get "Repository not found" immediately. With an HTTPS URL, if you're routinely using HTTPS for Git, you probably have credentials saved and you might miss that something's not publicly accessible which should be.
Further, if you do have some problem like this then the issue's arguably less clear, as the behavior of a private or simply nonexistent HTTPS repo URL for users without saved credentials is to prompt for login, which can be confusing, making a user think they need a Github account or that there's some problem with theirs.
Like I said though, it's not really a big deal.
[url "git@github.com:foo/bar"]
insteadOf = git://github.com/foo/barIt's akin using HostName in an ssh config file, though with what I'd consider to be a kind of odd reversed directionality to how you define it (and obviously letting you protocol-jump like this).